Turbine blade cooling

Abstract

A gas turbine engine vane or blade comprises a plurality of micro-structures disposed on an internal surface of the outer wall. The micro-structures may comprise an array of fins having a thickness of less than 0.002″, for example. Cooling air may be impinged upon the surface and routed through at least one flow channel to convectively cool the outer wall. Additionally or alternatively, micro-channels may be disposed along a suction side wall and pressure side wall of the vane or blade to convectively cool the respective walls. An embodiment of a vane or blade in accordance with the present invention may be constructed from a plurality of thin metal foils, stacked and bonded together.

What is claimed is: 
     
         1 . An air impingement cooled turbine vane, having a plurality of stacked and bonded metal foils defining the turbine vane, the turbine vane having an internal air inlet plenum for receiving an inlet airflow into the turbine vane, at least a first foil of the stacked and bonded metal foils, comprising:
 an outer wall having an airfoil shape with a leading edge region, a pressure-side, a suction-side and a trailing edge, wherein said pressure-side and said suction-side extend between said leading edge region and said trailing edge;   at least a first inner wall spaced from an inside surface of said outer wall and extending along at least a portion of said leading edge region including a stagnation point of the turbine vane for said first foil, wherein said inside surface of said outer wall and an outside surface of said first inner wall at least partially define a first flow channel therebetween; and   a plurality of micro-structures extending from said inside surface of said outer wall into said flow channel, wherein air from said internal air inlet plenum passes into a first inlet of said first flow channel and across said plurality of micro-structures.   
     
     
         2 . The turbine vane of  claim 1 , wherein said plurality of micro-structures are integrally formed with said inside surface of said outer wall within said first flow channel. 
     
     
         3 . The turbine vane of  claim 2 , wherein a combined surface area of said inside surface of said outer wall within said flow channel and said plurality of micro-structures is at least ten (10) times a surface area of a reference inside surface of said outer wall within said first flow channel without said plurality of micro-structures. 
     
     
         4 . The turbine vane of  claim 3 , wherein said total surface area of said inside surface and said plurality of micro-structures is at least at least twenty (20) times a surface area of the reference inside surface without said plurality of micro-structures. 
     
     
         5 . The turbine vane of  claim 2 , wherein said plurality of micro-structures comprise a plurality of fins each having a first end connected to said inside surface of said outer wall. 
     
     
         6 . The turbine vane of  claim 4 , wherein said plurality of fins each have a second end connected to said outside surface of said inner wall. 
     
     
         7 . The turbine vane of  claim 4 , wherein said fins have a thickness that is less than a thickness of said first foil having said outer wall. 
     
     
         8 . The turbine vane of  claim 1 , wherein said inner wall is spaced from said outer wall a distance that is between about 0.5% and about 5% of a chord length of the first foil as measured between the stagnation point and the trailing edge. 
     
     
         9 . The turbine vane of  claim 1 , wherein the turbine vane further comprises:
 an internal air outlet plenum for exhausting airflow out of the turbine vane, wherein air passing out of an outlet of the flow channel passes into the air outlet plenum.   
     
     
         10 . The turbine vane of  claim 1 , wherein said outer wall further comprises:
 at least a first bleed port extending through said outer wall, wherein at least a portion of air passing out of an outlet of the flow channel passes out of said bleed port.   
     
     
         11 . The turbine vane of  claim 1 , further comprising:
 at least a second inner wall spaced from an inside surface of said outer wall and extending along at least a portion of one of said suction-side and said pressure-side, wherein said inside surface of said outer wall and an outside surface of said second inner wall at least partially define a second flow channel therebetween and wherein air from the internal air inlet plenum passes into a second inlet of said second flow channel.   
     
     
         12 . The turbine vane of  claim 1 , further comprising:
 at least a second foil of the stacked and bonded metal foils, including an outer wall having a substantially similar airfoil shape, wherein the second foil has a planar top or bottom surface bonded to a planer top or bottom surface of said first foil, wherein said first foil and said second foil collectively define said first flow channel.   
     
     
         13 . The turbine vane of  claim 1 , wherein said first inlet is disposed between first and second ends of said inner wall, wherein a first portion of air passing into said first inlet passes through said first flow channel in a first direction and a second portion of the air passing into said first inlet passes through said first flow channel in a second direction. 
     
     
         14 . A vane configured for use in a turbine engine, comprising:
 a housing, wherein said housing extends longitudinally along a first axis and is airfoil-shaped to receive combustion air flow travelling in a direction substantially transverse to the first axis at a leading edge and divert a portion of the combustion air flow around a suction-side of the housing and another portion of the combustion air flow around a pressure-side of the housing, and wherein the housing has an internal core comprising a network of cooling air flow channels defined by a plurality of walls;   an inlet configured to route cooling air into the internal core;   an outlet configured to route heated cooling air from the internal core; and   an impingement channel configured to receive cooling air from the inlet and direct at least a portion of said cooling air across a plurality of micro-structures disposed in said impingement channel, wherein each of said plurality of micro-structures is disposed upon an internal side of a portion of an external wall of said housing defining an outer wall of said impingement channel.   
     
     
         15 . The vane of  claim 14 , wherein the portion of the external wall of said housing comprises at least a portion of the leading edge. 
     
     
         16 . The vane of  claim 15 , wherein the plurality of micro-structures comprises a plurality of fins, each fin having a nominal thickness in a direction transverse to a direction of cooling air flow through the impingement channel. 
     
     
         17 . The vane of  claim 16 , wherein each of the plurality of fins is secured to an internal shroud at an end of each fin opposite an end secured to the internal side of the external wall, said internal shroud defining an inner wall of said impingement channel. 
     
     
         18 . The vane of  claim 17 , wherein the vane comprises a plurality of metallic foils stacked in a direction of the first axis, said plurality of metallic foils secured in a bonded configuration such that a portion of each foil comprises a portion of the network of cooling air flow channels. 
     
     
         19 . The vane of  claim 18 , wherein at least two adjacent metallic foils comprise fins, wherein a maximum thickness of said fins is less than a thickness of said metallic foils. 
     
     
         20 . The vane of  claim 19 , wherein the thickness of said metallic foils is approximately 0.002″. 
     
     
         21 . The vane of  claim 18 , wherein a first of two adjacent metallic foils comprises fins in an area of the first metallic foil corresponding to the leading edge, said fins having a maximum thickness equal to a maximum thickness of said first metallic foil, and a second of said two adjacent metallic foils comprises a void in an area of said second metallic foil corresponding to the leading edge, wherein cooling air may pass through said void adjacent to said fins when said two adjacent metallic foils are disposed in the bonded configuration.